int i = 1234;
char[] chars = ("" + i).toCharArray();

Yeah, we’re missing a stream method to produce a char array. Maybe a whole CharStream class. In any case, no, you cannot cast between int[] and char[].

In the meantime, it’s getting a long line, but it works:

    return IntStream.rangeClosed('a', 'z')
            .mapToObj(c -> Character.toString((char) c))
            .collect(Collectors.joining())
            .toCharArray();

This gives a char[] containing

[a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z]

Maybe you are asking for:

Character.toChars(65) // returns ['A']

More info: Character.toChars(int codePoint)

Converts the specified character (Unicode code point) to its UTF-16 representation stored in a char array. If the specified code point is a BMP (Basic Multilingual Plane or Plane 0) value, the resulting char array has the same value as codePoint. If the specified code point is a supplementary code point, the resulting char array has the corresponding surrogate pair.

There are a number of issues with your solution. The first is the loop condition i > raw.length() is wrong - your loops is never executed - thecondition should be i < raw.length()

The second is the cast. You're attempting to cast to an integer array. In fact since the result is a char you don't have to cast to an int - a conversion will be done automatically. But the converted number isn't what you think it is. It's not the integer value you expect it to be but is in fact the ASCII value of the char. So you need to subtract the ASCII value of zero to get the integer value you're expecting.

The third is how you're trying to print the resultant integer array. You need to loop through each element of the array and print it out.

    String raw = "1233983543587325318";

    int[] num = new int[raw.length()];

    for (int i = 0; i < raw.length(); i++){
        num[i] = raw.charAt(i) - '0';
    }

    for (int i : num) {
        System.out.println(i);
    }